code: def _medfilt2d(self, threads):
      with ThreadPoolExecutor(max_workers=threads) as pool:
          wait(
              {
                  pool.submit(medfilt2d, chunk, 5)
                  for chunk in self.chunks
              }
          )
  
imports: import numpy
  import timeit
  from concurrent.futures import ThreadPoolExecutor, wait
  from .common import Benchmark, safe_import
label_desc: Use image node_id 2 for calling the MedFilt2D obj's underlying member method code with example usage: obj._medfilt2d(threads) without return types